Tubular electromagnetic relay having a spring armature



TUBULAR ELIEC'EROMAGNETICRELAY HAVING SPRING ARMATURE June 13. 1967 R PEEK. JR. ETAL Filed April 12, 1966 FIG. 4 FIG. 3

Robert L. PeeK, Jr.

William C. Slouson,

INVENTORS.

Wm. Ba/ r0 15" M J. Kv y Patented June 13, 1967 3,325,755 TUBULAR ELECTRGMAGNETIC RELAY HAVING A SPRING ARMATURE Robert Lee Peek, .lr., (Ottawa, Ontario, Canada, and Willliam C. Slauson, Columbus, Uhio, assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Apr. 12, 1966, Ser. No. 542,123 2 (Jlaims. (Ci. 335-187) The invention relates to an improved tubular relay and more specifically to a spring armature positively positioned and free of bind or friction with ease of movement between contacts in a tubular relay.

The spring armature of the present invention is a circular plate cut to provide a spring support over a portion of its periphery. The end of the spring member has a slight offset, which is welded to an outer pole face member. The spring member deflects as a partial turn of a helical spring. The rest of the armature is a rigid plate, providing a magnetic path from the outer pole face to the inner pole face, completing the circuit in the tubular relay.

The device of the present invention comprises an improvement in the art of tubular relays whereby the spring type armature does not bind against the side of the tubular case as is the case where the armature is a free floating cupped plate. In the free floating cupped plate type armature, made slightly smaller than the inside diameter of the tube, trouble was found in the failure of the release. Also, defective performance was ascribed to the binding of the armature against the inside of the tubular case, to which it was attracted magnetically. To alleviate such faulty performance a spring mounted type armature of the present invention was substituted which could be positively positioned free of bind or friction.

To expedite this change, it is desired to minimize the parts affected. One method found to be feasible was to cut the tubular case short and use its end as the outer pole face mating with the armature, using a larger tube member to enclose the armature and the back contact member. Another method found to work was in leaving the tubular case the same length and inserting a ring member used as the outer pole face and mating the armature to the end of the ring member.

Accordingly, an object of the present invention is to provide a tubular relay with an armature that is fast acting.

Another object of the invention is to provide an armature in a tubular relay that is relatively free of binding on the sides of the tubular casing.

Other objects and many of the attendant advantages of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which:

FIGURE 1 is a sectional view illustrating a first embodiment of a tubular relay according to the invention;

FIGURE 2 is a sectional view illustrating a second em- 7 bodiment of a tubular relay according to the invention;

FIGURE 3 is an expanded side view showing the spring armature details of FIGURE 1 and FIGURE 2; and

FIGURE 4 illustrates an end view of the spring armature section of FIGURE 3.

Referring to FIGURE 1, magnetic core 1 is located in the center of tubular relay 20. Surrounding magnetic core 1 is coil 2 and magnetic case 3, functioning as the outer pole piece. When coil 2 is energized, spring armature 9 will be pulled into contact with inner pole piece 4 connecting a magnetic circuit from magnetic case 3 through spring armature 9 and into magnetic core 1 by way of inner pole piece 4. Lock ring 5 is used to secure magnetic core 1 and inner pole piece 4 in the center of tubular relay 20. With coil 2 unactivated, spring armature 9 is predefiected such that contact is made with back contact 6. Back contact 6 is held in place by case extension 11 that holds outer ring 8 and insulator 7 tightly against back contact 6.

The embodiment illustrated in FIGURE 2 is similar to that shown in FIGURE 1 except that it utilizes a different flux path. The flux path now extends from magnetic case 3 through inner ring 10 and spring armature 9 to inner pole piece 4 and on into magnetic core 1. Inner pole piece 4, outer ring 8, and insulator 7 are dimensionally smaller than correspondingly illustrated in FIG- URE 1.

In FIGURE 3, an expanded side view is shown of the spring armature as it is connected to outer pole piece 3 and predefiected out from the inner pole piece 4. Dimension h is the thickness of the spring armature.

In FIGURE 4, an end view of FIGURE 3 is shown wherein the helical spring 9' has a width b. Radius R shows the radius of the solid armature.

The armature design involves both mechanical and magnetic considerations. The armature must have sufficient section to carry a field which exerts forces able to overcome the back contact force caused by predeflection of the spring, and to supply the desired front contact force over and above the force required to move the armature to the operated, or closed, position. The stiffness of the spring arm should be of 1 to 2 kilodynes per mil-inch to provide the back force with reasonable tolerances on the predeflection and to avoid an excessive spring load in the operated position. Thus, magnetically, the armature must have sufiicient section to carry a field which supplies adequate forces for operation.

Assembly of the spring amature is accomplished by the following steps. As shown in FIGURE 3 the offset portion of the armature arm is welded to the outer pole face 3, and the arm is then bent to provide a travel at the center pole face well in excess of that required to develop the desired retractile force, i.e., back contact force plus spring build-up in the actual travel. Then, before assembling the back contact, the armature is operated by energizing the coil, and the spring arm takes a permanent set, with armature in operate position. Now, the back contact member is assembled, connected to give continuity to the front pole face and then back off 7 mil-inches to allow that much free travel for the armature.

While many changes in constructional details and features may become apparent to those skilled in the art, in view of the illustrtaed preferred form shown and described herein, we desire to be limited only by the scope and spirit of the appended claims.

We claim:

1. A tubular electromagnetic relay comprising a center magnetic core having an inner pole face attached at an end of said core, an energizing coil surrounding said core, an outer pole face positioned annularly about said energizing coil, a spring armature fixedly attached to said outer pole face positioned so that activation of said energizing coil will cause said spring armature to be contacted with said inner pole face, wherein said armature is a disc with a cutout over a portion of its periphery forming a helical spring.

2. A tubular electromagnetic relay as set forth in claim 1 wherein said helical spring portion of said armature is offset at its end and welded to said outer pole face.

References Cited UNITED STATES PATENTS 541,243 6/1895 Manger 200159 2,752,450 6/1956 Foulkes et al 335-196 X 3,118,988 1/1964 Nitsch 335-202 X BERNARD A. GILHEANY, Primary Examiner. R. N. ENVALL, J. J. BAKER, Assistant Examiners. 

1. A TUBULAR ELECTROMAGNETIC RELAY COMPRISING A CENTER MAGNETIC CORE HAVING AN INNER POLE FACE ATTACHED AT AN END OF SAID CORE, AN ENERGIZING COIL SURROUNDING SAID CORE, AN OUTER POLE FACE POSITIONED ANNULARLY ABOUT SAID ENERGIZING COIL, A SPRING ARMATURE FIXEDLY ATTACHED TO SAID OUTER POLE FACE POSITIONED SO THAT ACTIVATION OF SAID ENERGIZING COIL WILL CAUSE SAID SPRING ARMATURE TO BE CONTACTED 